CN110042411B

CN110042411B - Water electrolysis device

Info

Publication number: CN110042411B
Application number: CN201910035996.2A
Authority: CN
Inventors: 山本和裕; 小林干哉
Original assignee: Honda Motor Co Ltd
Current assignee: Honda Motor Co Ltd
Priority date: 2018-01-16
Filing date: 2019-01-15
Publication date: 2021-08-10
Anticipated expiration: 2039-01-15
Also published as: JP6649414B2; CN110042411A; JP2019123901A; US20190218670A1; US10822708B2

Abstract

The present disclosure relates to water electrolysis devices. The differential pressure type high-pressure water electrolysis device (10) is provided with a flow path forming member (46) for supplying water to an anode. The flow path forming member (46) is provided with: a water receiving part (50a) for receiving water supplied from the outside; a distribution path (50b) for distributing the water flowing into the water receiving section (50 a); a collecting path (50e) into which water from the surplus supply part flows; and a water discharge unit (50f) that receives the water in the collection path (50e) and discharges the water to the outside. The distribution path (50b) and the collection path (50e) are displaced from the position of the seal member (72) facing the pressure-resistant member (74) surrounding the seal member (72) from the outside.

Description

Water electrolysis device

Technical Field

The present invention relates to a water electrolysis apparatus for electrolyzing water to generate oxygen and hydrogen.

Background

A water electrolysis apparatus is known as an apparatus that electrolyzes water to generate hydrogen (and oxygen), and the obtained hydrogen is supplied to a fuel cell, for example, and used as a fuel gas.

More specifically, the water electrolysis device includes an electrolyte membrane-electrode assembly in which an anode electrode catalyst layer is formed on one surface of an electrolyte membrane made of a solid polymer, and a cathode electrode catalyst layer is formed on the other surface. The electrolyte membrane-electrode structure is sandwiched between power supply bodies disposed outside the anode electrode catalyst layer and the cathode electrode catalyst layer, respectively. When electric power is supplied to the membrane electrode assembly via the power supply body, water is electrolyzed at the anode electrode catalyst layer, thereby generating hydrogen ions (protons) and oxygen gas. The protons therein move to the cathode electrode catalyst layer through the electrolyte membrane, and combine with the electrons to become hydrogen gas. On the other hand, oxygen gas generated in the anode electrode catalyst layer is discharged from the water electrolysis device together with the remaining water.

Here, the hydrogen gas generated in the cathode electrode catalyst layer may be obtained at a higher pressure than the oxygen gas generated in the anode electrode catalyst layer. Such water electrolysers are known as pressure differential high pressure water electrolysers. In the differential pressure type high pressure water electrolysis apparatus, since the internal pressure on the cathode side becomes large, a seal member (for example, an O-ring) for preventing leakage of hydrogen gas and a pressure-resistant member surrounding the seal member from the outside are provided on the cathode side.

As described in japanese patent application laid-open No. 2016-. The flow passage has a water receiving portion for receiving water, a supply passage for supplying water to the anode catalyst layer, and a water discharge portion for discharging water not decomposed in the remaining supply portion, and an arc-shaped distribution passage and a collection passage are inserted between the water receiving portion and the supply passage, and between the supply passage and the water discharge portion.

Disclosure of Invention

A main object of the present invention is to provide a water electrolysis apparatus capable of preventing a large deflection of an electrolyte membrane or the like even when a pressing force (japanese pressure) of a sealing member against a pressure-resistant member or the electrolyte membrane is increased by generation of high-pressure hydrogen gas.

According to an embodiment of the present invention, there is provided a water electrolysis apparatus including:

an anode-side separator;

a cathode side separator;

an electrolyte membrane-electrode assembly, which is configured by providing an anode electrode catalyst layer and a cathode electrode catalyst layer on an electrolyte membrane, between the anode-side separator and the cathode-side separator;

an anode power supply body that applies power to the anode electrode catalyst layer;

a cathode power supply that applies power to the cathode electrode catalyst layer;

a seal member that is sandwiched between the cathode-side separator and the membrane electrode assembly, and surrounds the cathode electrode catalyst layer; and

a pressure-resistant member surrounding the sealing member from the outside,

wherein the water electrolysis apparatus further has a flow path forming member,

the flow path forming member is formed with: a water receiving part for receiving water; a plurality of supply paths that supply the water to the anode catalyst layer, respectively; a distribution path connected to the water receiving part and the plurality of supply paths, for distributing the water to the plurality of supply paths; a water discharge portion for discharging undecomposed water; and a collecting path connected to the plurality of supply paths and the water discharge unit for collecting the undecomposed water,

when a cross section of the water electrolysis apparatus perpendicular to a direction in which the membrane electrode assembly is sandwiched between the anode-side separator and the cathode-side separator is viewed, the distribution passage and the collection passage are located at positions offset from the sealing member.

That is, in this structure, the distribution manifold and the collection manifold are located at positions not overlapping with the seal member. In other words, one end surface of the flow passage forming member overlaps with the sealing member. Thus, when the sealing member is pressed from the inner peripheral side by the hydrogen gas generated at high pressure and thus pressed against the pressure-resistant member and the electrolyte membrane, the electrolyte membrane is supported by the flow passage forming member. Therefore, even if the hydrogen gas is at a high pressure, the electrolyte membrane and the flow passage forming member are less likely to undergo large elastic deformation (deflection).

Therefore, a decrease in the contact surface pressure (japanese: contact surface pressure) between the pressure-resistant member and the electrolyte membrane can be avoided. Thus, the sealing member pressed against the pressure-resistant member by the pressure of the hydrogen gas can be suppressed from entering the gap between the pressure-resistant member and the electrolyte membrane, in other words, from entering (protruding) between the pressure-resistant member and the electrolyte membrane. This can prevent damage to the sealing member, such as air tightness failure.

The distribution path and the collection path may be provided outside of a position where the sealing member and the pressure-resistant member face each other, for example. In this case, the deflection can be effectively suppressed.

Preferably, the distribution path and the collection path are located outward of the outer peripheral end of the membrane electrode assembly. This is because the deflection of the membrane electrode assembly can be further suppressed by this structure.

Preferably, the distribution road and the collection road are in the shape of a circular arc. By adopting such a shape, water can be supplied to the entire anode (anode power supply body and anode electrode catalyst layer) substantially uniformly and in a sufficient amount.

According to the present invention, the distribution channel and the collection channel, which are formed in the flow channel forming member and are part of the flow channel through which water to be electrolyzed flows, are provided at offset positions that do not overlap with the sealing member that seals the cathode (cathode power supply body and cathode electrode catalyst layer). Therefore, since the flow passage forming member supports the electrolyte membrane, the electrolyte membrane and the flow passage forming member are less likely to undergo large elastic deformation (deflection) when the sealing member is pressed from the inner peripheral side to be pressed against the pressure-resistant member and the electrolyte membrane.

As a result, a decrease in the contact surface pressure between the pressure-resistant member and the electrolyte membrane can be avoided. Thus, the sealing member subjected to the pressing of the hydrogen gas can be suppressed from entering (protruding into) the gap between the pressure-resistant member and the electrolyte membrane. This can prevent the seal member from being damaged.

The objects, features and advantages will be readily understood from the following description of the embodiments with reference to the accompanying drawings.

Drawings

Fig. 1 is a schematic overall perspective view of a differential pressure type high-pressure water electrolysis apparatus (water electrolysis apparatus) according to an embodiment of the present invention.

Fig. 2 is an exploded perspective view of a high-pressure water electrolysis cell constituting the differential pressure type high-pressure water electrolysis apparatus of fig. 1.

Fig. 3 is a sectional view in the direction of the arrows on the line III-III in fig. 2.

Fig. 4 is a schematic bottom view of a water flow path member (flow path forming member) constituting the high-pressure water electrolytic cell.

Fig. 5 is an enlarged sectional view of a main portion showing a state in which the large O-ring in fig. 3 is compressed by being pressed from the inner peripheral wall side.

Fig. 6 is an enlarged sectional view of a main portion showing a state in which a large O-ring (sealing member) is pressed and compressed from the inner peripheral wall side in a high-pressure water electrolytic cell in which a distribution path and a collection path are arranged to overlap opposing positions of the large O-ring as a sealing member and a pressure-resistant member.

Detailed Description

Hereinafter, a water electrolysis apparatus according to the present invention will be described in detail with reference to the accompanying drawings by referring to preferred embodiments.

Fig. 1 is a schematic overall perspective view of a differential pressure type high-pressure water electrolysis apparatus 10 (water electrolysis apparatus) according to the present embodiment. The differential pressure type high-pressure water electrolysis apparatus 10 includes a laminated body 14 in which a plurality of high-pressure water electrolysis cells 12 are laminated. In fig. 1, the high-pressure water electrolysis cells 12 are stacked in the vertical direction (the direction of arrow a), but may be stacked in the horizontal direction (the direction of arrow B). As described above, in the present embodiment, a direction in which the respective constituent portions are superimposed on each other is defined as a stacking direction.

Terminal plate 16a, insulating plate 18a, and end plate 20a, each having a substantially circular disk shape, are disposed in this order from below toward above at one end (upper end) of stacked body 14 in the stacking direction. Similarly, terminal plate 16b, insulating plate 18b, and end plate 20b, each having a substantially circular disk shape, are disposed in this order from the top toward the bottom at the other end (lower end) of stacked body 14 in the stacking direction.

In the differential pressure type high-pressure water electrolysis apparatus 10, the

end plates

20a and 20b are integrally tensioned and held by four links 22 extending in the arrow a direction and are fastened and connected in the stacking direction. Further, the differential pressure type high pressure water electrolysis apparatus 10 may have the following structure: the integrated structure is held by a box-shaped case (not shown) including the

end plates

20a and 20b as end plates. The differential pressure type high-pressure water electrolysis apparatus 10 has a substantially cylindrical shape as a whole, but may be formed in various shapes such as a cubic shape.

Terminal portions

24a and 24b are provided on side portions of the

terminal plates

16a and 16b so as to protrude outward. The

terminal portions

24a and 24b are electrically connected to an electrolytic power supply 28 via

lead wires

26a and 26 b.

As shown in fig. 2 and 3, the high-pressure water electrolysis cell 12 includes a substantially circular disk-shaped membrane electrode assembly 30, and an anode side separator 32 and a cathode side separator 34 that sandwich the membrane electrode assembly 30. The sandwiching direction in which the membrane electrode assembly 30 is sandwiched between the anode-side separator 32 and the cathode-side separator 34 is the a direction (stacking direction).

A resin frame member 36 having a substantially annular shape is disposed between the anode separator 32 and the cathode separator 34. The membrane electrode assembly 30 and the like are housed in the hollow interior of the resin frame member 36.

Sealing members

37a and 37b are provided on the upper opening bottom and the lower opening bottom of the resin frame member 36. The anode separator 32 and the cathode separator 34 close the bottom of the upper opening and the bottom of the lower opening of the resin frame member 36 by the sealing

members

37a and 37b, respectively.

At one end of the resin frame member 36 in the radial direction, water supply communication holes 38a are provided, and the water supply communication holes 38a communicate with each other in the stacking direction (the direction of arrow a) to supply water (pure water). Further, a water discharge communication hole 38b is provided at the other end in the diameter direction of the resin frame member 36, and this water discharge communication hole 38b is used for discharging oxygen gas generated by the reaction and unreacted water (mixed fluid).

As shown in fig. 1, a water supply port 39a communicating with the water supply communication hole 38a is connected to a side portion of the resin frame member 36 disposed lowermost in the stacking direction. Further, a water discharge port 39b communicating with the water discharge communication hole 38b is connected to a side portion of the resin frame member 36 disposed uppermost in the stacking direction.

A high-pressure hydrogen gas communication hole 38c is provided in the center of the high-pressure water electrolyzer 12, and the high-pressure hydrogen gas communication holes 38c penetrate through the substantial center of the electrolysis region and communicate with each other in the stacking direction (see fig. 2 and 3). The high-pressure hydrogen passage 38c discharges hydrogen gas generated by the reaction and having a higher pressure (for example, 1 to 80MPa) than oxygen gas generated by the same reaction.

The anode-side separator 32 and the cathode-side separator 34 have a substantially circular disk shape, and are constituted of, for example, a carbon member or the like. The anode-side separator 32 and the cathode-side separator 34 may be obtained by press forming other steel sheets, stainless steel sheets, titanium sheets, aluminum sheets, plated steel sheets, or metal sheets having metal surfaces subjected to surface treatment for corrosion prevention. Alternatively, the surface treatment for corrosion prevention may be performed after the cutting.

The membrane electrode assembly 30 includes an electrolyte membrane 40 formed of a solid polymer membrane having a substantially annular shape. The electrolyte membrane 40 is sandwiched by an anode power-supplying body 42 and a cathode power-supplying body 44 for electrolysis having annular shapes. The electrolyte membrane 40 is made of, for example, a Hydrocarbon (HC) based membrane or a fluorine based solid polymer membrane.

An anode electrode catalyst layer 42a having a ring shape is provided on one surface of the electrolyte membrane 40. A cathode electrode catalyst layer 44a having a ring shape is formed on the other surface of the electrolyte membrane 40. For example, a Ru (ruthenium) catalyst is used for the anode electrode catalyst layer 42a, and a platinum catalyst is used for the cathode electrode catalyst layer 44 a. The high-pressure hydrogen gas communication hole 38c is formed in substantially the center of the electrolyte membrane 40, the anode electrode catalyst layer 42a, and the cathode electrode catalyst layer 44 a.

The anode power supply 42 and the cathode power supply 44 are made of, for example, a sintered body (porous conductor) of spherical atomized titanium powder (japanese: spherical アトマイズチタン powder). The anode power supply 42 and the cathode power supply 44 are provided with smooth surface portions which are etched after polishing, and the porosity is set in the range of 10% to 50%, more preferably 20% to 40%. The frame 42e is fitted to the outer peripheral edge of the anode power supply body 42. The frame portion 42e is formed more densely than the anode power supply body 42. Further, the outer peripheral portion of the anode power supply body 42 can be made dense, and thus the outer peripheral portion can be made the frame portion 42 e.

An anode chamber 45an for housing the anode power supply body 42 is formed by the hollow interior of the resin frame member 36 and the anode side separator 32. On the other hand, a cathode chamber 45ca for accommodating the cathode power supply body 44 is formed by the hollow interior of the resin frame member 36 and the cathode side separator 34.

A water flow path member 46 as a flow path forming member is interposed between the anode side separator 32 and the anode power supply body 42 (anode chamber 45 an). As shown in fig. 2, the water flow path member 46 has a substantially circular disk shape, and an inlet protrusion 46a and an outlet protrusion 46b are formed at an outer peripheral portion with a phase difference of substantially 180 °.

A water flow path for supplying water to be electrolyzed to the anode and discharging the remaining supply part of the water is formed in the water flow path member 46. The water flow path is configured to include a water receiving portion 50a, a distribution path 50b, a notch groove 50c, a hole portion 50d, a collecting path 50e, and a discharge connection path 50f from the upstream side in the flow direction. The following description will be made separately.

A water receiving portion 50a as a water receiving portion that receives water supplied from the water supply communication hole 38a is formed in the inlet protrusion 46 a. The distribution passage 50b is connected to the water receiving portion 50 a. On the other hand, a collection passage 50e is formed in the vicinity of the outlet protrusion 46b, and a discharge connection passage 50f (water discharge portion) connected to the collection passage 50e is formed in the outlet protrusion 46 b. The water receiving portion 50a, the distribution passage 50b, the collection passage 50e, and the discharge connection passage 50f penetrate in the thickness direction of the water flow path member 46. The distribution path 50b and the collection path 50e are formed in an arc shape by curving along the outer peripheral edge of the water flow path member 46.

As shown in fig. 4, a plurality of slit grooves 50c are formed on the lower surface of the water flow passage member 46 facing the anode-side separator 32, extending from the distribution passage 50b to the collection passage 50 e. The notch groove 50c is mostly parallel to the diameter of the water flow path member 46, but partially bent so as to bypass the high-pressure hydrogen communication hole 38 c. The height of the notch groove 50c is approximately 1/2 a of the thickness of the water flow path member 46.

On the other hand, a plurality of holes 50d extending in the thickness direction thereof and reaching the notch grooves 50c are formed in the upper surface of the water flow passage member 46 facing the membrane electrode assembly 30. The hole 50d opens toward the anode power supply body 42. Since the distribution passage 50b communicates with the notch groove 50c and the notch groove 50c communicates with the hole 50d, the water received by the water receiving portion 50a is supplied to the anode power supply body 42 through the distribution passage 50b, the notch groove 50c, and the hole 50 d. That is, the notch groove 50c and the hole 50d function as a supply passage for supplying water to the anode (the anode power supply body 42 and the anode electrode catalyst layer 42 a).

In the water channel member 46 having such a configuration, the distribution channel 50b and the collection channel 50e are located outward from the facing position of the large O-ring 72 and the pressure-resistant member 74, which will be described later, and are located outward from the outer peripheral end of the membrane electrode assembly 30.

A protective sheet member 48 is interposed between the anode power supply body 42 and the anode electrode catalyst layer 42 a. The protective sheet member 48 is disposed on the inner periphery thereof inward of the inner peripheries of the anode current collector 42 and the cathode current collector 44, and the outer peripheral position thereof is set to the same position as the outer peripheral positions of the electrolyte membrane 40, the anode current collector 42, and the water flow path member 46. The protective sheet member 48 has a plurality of through holes 48a provided in a range (electrolysis region) facing the anode electrode catalyst layer 42a in the stacking direction, and has a frame portion 48b outside the electrolysis region. The frame 48b has, for example, a rectangular hole (not shown).

A communication hole member 52 that surrounds the high-pressure hydrogen communication hole 38c is disposed between the anode-side separator 32 and the electrolyte membrane 40. The communication hole member 52 has a substantially cylindrical shape, and

seal chambers

52a and 52b cut out in the shape of circular cutouts are provided at both ends in the axial direction. Sealing members (small O-rings) 54a and 54b for sealing around the high-pressure hydrogen communication hole 38c are disposed in the sealing

chambers

52a and 52 b. Groove 52s for disposing protective sheet member 48 is formed in the end face of communication hole member 52 facing electrolyte membrane 40.

A cylindrical porous member 56 is disposed between the

seal chambers

52a and 52b and the high-pressure hydrogen gas communication hole 38 c. The high-pressure hydrogen gas communication hole 38c is formed in the center of the porous member 56. The porous member 56 is interposed between the anode side separator 32 and the electrolyte membrane 40. The porous member 56 is formed of a porous body made of ceramic, a porous body made of resin, or a porous body made of a mixed material of ceramic and resin, but various other materials may be used.

As shown in fig. 2 and 3, a load applying mechanism 58 is disposed in the cathode chamber 45ca, and the load applying mechanism 58 is configured to press the cathode power supply 44 toward the electrolyte membrane 40. The load applying mechanism 58 is configured to include an elastic member, for example, a plate spring 60, and the plate spring 60 applies a load to the cathode power supply body 44 via a metal plate spring seat (spacer member) 62. In addition, a coil spring, or the like can be used as the elastic member in addition to the plate spring 60.

A conductive sheet 66 is disposed between the cathode power supply 44 and the plate spring holder 62. The conductive sheet 66 is made of a metal sheet such as titanium, sus, or iron, has a ring shape, and is set to have substantially the same diameter as the cathode power supply 44.

An insulating member, for example, a resin sheet 68 is disposed in the center of the cathode power supply 44 so as to be positioned between the conductive sheet 66 and the electrolyte membrane 40. The resin sheet 68 is fitted to the inner peripheral surface of the cathode power supply body 44. The resin sheet 68 is set to be substantially the same thickness as the cathode power supply body 44. As the resin sheet 68, for example, PE N (polyethylene naphthalate), a polyimide film, or the like is used.

A communication hole member 70 is disposed between the resin sheet 68 and the cathode side separator 34. The communication hole member 70 has a cylindrical shape, and a high-pressure hydrogen communication hole 38c is formed in the center. A hydrogen gas discharge passage 71 that communicates the cathode chamber 45ca with the high-pressure hydrogen gas communication hole 38c is formed at one axial end of the communication hole member 70.

In the cathode chamber 45ca, a large O-ring 72 (seal member) is disposed so as to surround the outer peripheries of the cathode power supply body 44, the plate spring holder 62, and the conductive plate 66. A pressure-resistant member 74 having a hardness higher than that of the large O-ring 72 is disposed on the outer periphery of the large O-ring 72. The pressure-resistant member 74 has a substantially annular shape, and the outer peripheral portion thereof is fitted to the inner peripheral portion of the resin frame member 36.

As shown in fig. 3 and 4, the inner peripheral wall of the large O-ring 72 is separated from the cathode power supply body 44, the conductive sheet 66, the plate spring holder 62, and the plate spring 60. The gap resulting from this separation is a pressure application chamber 76 forming a part of the cathode chamber 45 ca. When the hydrogen gas generated in the cathode electrode catalyst layer 44a enters the cathode chamber 45ca, it also enters the pressure application chamber 76 as a part thereof.

The differential pressure type high-pressure water electrolysis apparatus 10 according to the present embodiment is basically configured as described above, and the operational effects thereof will be described in relation to the operation of the differential pressure type high-pressure water electrolysis apparatus 10.

When the electrolysis of water is started, as shown in fig. 1, water is supplied from the water supply port 39a to the water supply communication hole 38a, and electric power from the electrolysis power supply 28 is applied to the

terminal portions

24a and 24b of the

terminal plates

16a and 16b via the

lead wires

26a and 26 b. Therefore, as shown in fig. 3, in each high-pressure water electrolysis cell 12, water supplied from the outside passes through the water receiving portion 50a from the water supply communication hole 38a to reach the distribution passage 50 b.

Since the distribution passage 50b has an arc shape, the water flows along the distribution passage 50b near the outer peripheral edge of the water flow passage member 46 and then flows into each of the plurality of notch grooves 50c formed in the lower surface of the water flow passage member 46. By forming the distribution path 50b in an arc shape in this manner, the flow resistance is reduced, and water can be distributed substantially uniformly to the notch groove 50c constituting the supply path. And the amount of water is also sufficient.

The water circulates along the slit groove 50c and is distributed to each of the plurality of holes 50d in the middle thereof. The water flowing into the hole 50d is supplied from the hole 50d to the anode current collector 42, and moves in the anode current collector 42, which is a porous body.

The water further reaches the anode electrode catalyst layer 42a through the through holes 48 a. An anode reaction occurs in the anode electrode catalyst layer 42a, which electrolyzes water to generate protons, electrons, and oxygen. The protons in the electrolyte membrane 40 pass through and migrate to the cathode electrode catalyst layer 44a side, and a cathode reaction occurs in which the protons are combined with electrons. As a result, hydrogen gas in a gas phase can be obtained.

The water that is not distributed to the hole 50d and that has flowed through the remaining supply portion of the notch groove 50c flows into the collecting passage 50e and is collected. Since the collecting channel 50e is also arc-shaped, water flowing through each slit groove 50c is easily collected. The water collected in the collection passage 50e is discharged from the discharge connection passage 50f to the outside of the stack 14 through the water discharge port 39b together with the oxygen gas generated by the anode reaction.

On the other hand, the hydrogen gas flows into the cathode chamber 45c a along the hydrogen gas flow path inside the cathode power supply body 44, and is discharged from the hydrogen gas discharge passage 71 to the high-pressure hydrogen gas communication hole 38 c. The hydrogen gas can flow through the high-pressure hydrogen gas communication hole 38c while being maintained at a higher pressure than the water supply communication hole 38a, and can be taken out to the outside of the differential pressure type high-pressure water electrolysis apparatus 10.

The hydrogen gas generated by the cathode electrode catalyst layer 44a fills the cathode chamber 45ca including the pressure application chamber 76 as high-pressure hydrogen gas. Therefore, in each high-pressure water electrolytic cell 12, as shown in fig. 5, the large O-ring 72 is pressed toward the pressure-resistant member 74 along with the deformation. At this time, a pressing force in the normal direction is generated from the large O-ring 72 to the cathode side separator 34 and the electrolyte membrane 40 as the sandwiching members in the stacking direction.

As shown in fig. 6, it is assumed that the distribution path 50b and the collection path 50e overlap the opposing positions of the large O-ring 72 and the pressure-resistant member 74 in the cross section in the direction orthogonal to the stacking direction (clamping direction) of the high-pressure water electrolytic cell 12. Fig. 6 shows only the distribution path 50 b.

In this case, since a normal-direction pressing force applied to electrolyte membrane 40 by large O-ring 72 pressed by high-pressure hydrogen gas from the inner peripheral side acts on the hollowed portion (japanese: meat removal き) of distribution path 50b, frame 42e and protective sheet member 48 in the vicinity directly above distribution path 50b are likely to be partially bent. Since the electrolyte membrane 40 is thin and relatively flexible, the contact surface pressure is easily reduced immediately below the facing position of the large O-ring 72 and the pressure-resistant member 74 of the electrolyte membrane 40 due to local deflection of the frame portion 42e and the protective sheet member 48.

As understood from the above, the distribution passage 50b to the collection passage 50e are hollowed out portions formed through the water passage member 46, and therefore a sufficient reaction force cannot be given against the pressing of the electrolyte membrane 40 by the large O-ring 72. Therefore, the above-described deflection is relatively likely to occur. As a result, the contact surface pressure of the electrolyte membrane 40 and the pressure-resistant member 74 is reduced.

The large O-ring 72 is made of rubber or the like, and is therefore relatively flexible. Therefore, when the contact surface pressure is reduced, a part of the outer peripheral wall of the large O-ring 72 easily enters the contact surface pressure reduced portion. In other words, a part of the large O-ring 72 easily protrudes between the electrolyte membrane 40 and the pressure-resistant member 74.

In such a state, the sealing becomes insufficient. Further, when the generation of hydrogen gas is stopped and the inner peripheral wall side of the large O-ring 72 is returned to the normal pressure by the pressure release described later, there is a fear that the protruding portion of the large O-ring 72 is peeled off. When this occurs, damage to the large O-ring 72 results.

In contrast, in the present embodiment, as described above, the distribution path 50b and the collection path 50e are both offset from the facing position of the large O-ring 72 and the pressure-resistant member 74 and located outward of the facing position (see fig. 5). The distribution path 50b and the collection path 50e are located outward of the outer peripheral end of the membrane electrode assembly 30. Therefore, the upper surface of the water flow path member 46 is positioned below the facing position. The anode power supply body 42, the protective sheet member 48, and the electrolyte membrane 40 are supported by the upper surface.

Therefore, the anode power supply member 42, the protective sheet member 48, and the electrolyte membrane 40 can be suppressed from being flexed. Therefore, the contact surface pressure between the electrolyte membrane 40 and the pressure-resistant member 74 can be prevented from being lowered. This prevents the large O-ring 72 from entering (protruding) between the electrolyte membrane 40 and the pressure-resistant member 74.

When the operation of the differential pressure type high-pressure water electrolysis apparatus 10 is stopped to stop the electrolysis, the cathode chamber 45ca is subjected to pressure removal (pressure reduction) processing in order to eliminate the pressure difference between the anode chamber 45an on the low pressure side (normal pressure) and the cathode chamber 45ca on the high pressure side. As a result, the large O-ring 72 is unfolded and restored to its original shape, and is moved to its original position. At this time, the outer peripheral wall of the large O-ring 72 is easily moved inward in the diameter direction, in other words, easily returned to the original shape. This is because the outer peripheral wall of the large O-ring 72, which is pressed against the inner peripheral wall of the pressure-resistant member 74 when hydrogen gas is generated, is inhibited from entering (protruding into) the gap between the electrolyte membrane 40 and the pressure-resistant member 74.

Therefore, the protruding portion of the large O-ring 72 can be prevented from being peeled off, in other words, damaged, when the cathode is decompressed. Thus, a sufficient sealing capability can be obtained with the large O-ring 72.

The present invention is not particularly limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention.

For example, the distribution path 50b and the collection path 50e may be shifted inward from the facing position of the large O-ring 72 and the pressure-resistant member 74.

Claims

1. A water electrolysis device (10) having:

an anode-side separator (32);

a cathode-side separator (34);

an electrolyte membrane-electrode assembly (30) that is configured by providing an anode electrode catalyst layer (42a) and a cathode electrode catalyst layer (44a) on an electrolyte membrane (40), and that is located between the anode-side separator (32) and the cathode-side separator (34);

an anode power supply body (42) that applies power to the anode electrode catalyst layer (42 a);

a cathode power supply (44) that applies power to the cathode electrode catalyst layer (44 a);

a seal member (72) that surrounds the cathode electrode catalyst layer (44a) and is sandwiched between the cathode-side separator (34) and the membrane-electrode assembly (30); and

a pressure-resistant member (74) that surrounds the sealing member (72) from the outside,

wherein the water electrolysis device (10) is characterized in that,

further provided is a flow path forming member (46) which is formed with: a water receiving section (50a) for receiving water; a plurality of supply paths (50c, 50d) that supply the water to the anode catalyst layer (42a) individually; a distribution path (50b) which communicates with the water receiving section (50a) and the plurality of supply paths (50c, 50d) and distributes the water to the plurality of supply paths (50c, 50 d); a water discharge unit (50f) for discharging undecomposed water; and a collecting passage (50e) which communicates with the plurality of supply passages (50c, 50d) and the water discharge portion (50f) and collects the undecomposed water,

the distribution passage (50b) penetrates the passage forming member (46) in the direction in which the water receiving section (50a) and the membrane electrode assembly (30) are stacked,

the collection path (50e) penetrates the flow path forming member (46) in the direction in which the water discharge section (50f) and the membrane electrode assembly (30) are stacked,

the flow path forming member (46) has an inlet protrusion (46a) and an outlet protrusion (46b) protruding from the outer peripheral portion of the flow path forming member (46), the inlet protrusion (46a) and the outlet protrusion (46b) are formed in an anode chamber (45an) located between the distribution path (50b) and the anode power supply body (42),

the water receiving portion (50a) is formed at the inlet protrusion portion (46a), and the water discharging portion (50f) is formed at the outlet protrusion portion (46b),

the distribution path (50b) and the collection path (50e) are formed near the outer peripheral edge of the flow path forming member (46),

when a cross section of the water electrolysis device (10) that is orthogonal to a direction in which the membrane electrode assembly (30) is sandwiched between the anode-side separator (32) and the cathode-side separator (34) is viewed, the distribution path (50b) and the collection path (50e) are located at positions that are offset outward from the seal member (72) on a plane that is orthogonal to the stacking direction.

2. The water electrolysis device (10) according to claim 1,

the distribution path (50b) and the collection path (50e) are located outward of a position where the sealing member (72) and the pressure-resistant member (74) face each other.

3. The water electrolysis device (10) according to claim 1,

the distribution path (50b) and the collection path (50e) are located outward of the outer peripheral end of the membrane electrode assembly (30).

4. The water electrolysis device (10) according to claim 1,

the distribution path (50b) and the collection path (50e) are arc-shaped.